Correlation of the physical properties and the interface morphology of AlGaAs/GaAs heterostructures

Abstract

We have investigated the influence of interface roughness in GaAs/AlGaAs heterostructures on both the optical and the electronic properties by systematically varying the two growth parameters substrate temperature and growth interruption. We prove that the optimization of samples for optics and transport, respectively, requires different growth parameters. Whereas the optical properties are exclusively determined by the roughness of the two quantum well interfaces, the transport properties are additionally influenced by the ionized impurity scattering. The number of impurities increases during growth interruption and, consequently, in contrast to the optical samples, an optimization of the growth parameters is not as straightforward since it depends on the background impurities originating from the ultrahigh vacuum system. A direct correlation with information obtained from atomic force microscopy images is therefore only possible for the optical properties. At growth temperatures higher than 620 °C in addition to the usual terrace structure, a mesoscopic island structure appears and dominates the exciton luminescence linewidth.

Realistic heterointerface model for excitonic states in growth-interrupted GaAs quantum wells

“…For GI GaAs QWs with mixed crystal barriers 19,20,21 normally more than 2 ML peaks are present. This indicates that for mixed crystal barriers, the interface disorder is partly uncorrelated, as was also observed in structural investigations 22 . This finding can be understood considering that a Al x Ga 1−x As mixed crystal growth surface consists essentially only of Ga atoms that are mobile.…”

The influence of growth interruption on the luminescence properties of Ga(As,Sb)-based type II heterostructures

“…(Ga,In)As shows the same behaviour known for GaAs [20]. The growth interruption actually leads to the formation of big, smooth terraces, which starts already with 10s GI and is fully developed with GI of 120s.…”

Relationship of growth mode to surface morphology and dark current in InAlAs/InGaAs avalanche photodiodes grown by MBE on InP

“…In particular, it was empirically found that APDs fabricated from wafers with moderately rough surfaces tended to exhibit high dark leakage currents. Similar observations have been reported in the past relating interface morphology in heterostructures to optical and electronic properties, such as photoluminescence (PL) line width, electron mobility, and transport lifetimes [4][5][6]. This paper examines the impact of growth conditions upon wafer morphology and presents an empirical relationship between surface roughness and APD dark current.…”